<p>The consensus in philosophy of biology seems to be that although nothing in biological systems is strictly incompatible with physical laws, biology is to a very great extent autonomous from physics. The main thesis of this paper is that, although biology is autonomous from the physical sciences in several ways, it is not explanatorily independent from physics. Physical explanations are pervasive and important in biology, including in evolutionary biology. The paper presents three case studies of physical explanations in evolutionary biology: a case of adaptation to pressure in deep-sea invertebrates, which illustrates how a physical parameter imposes selective pressures that organisms adapt to by changing their own physical properties; the case of water viscosity and the evolution of multicellularity, which shows how a global change in a physical parameter is thought to have triggered a macroevolutionary event; and the case of quantum tunnelling in respiration, which shows how quantum physics is relevant to the evolution of sex in eukaryotes.</p>